Package org.apache.commons.collections4.multimap

Class AbstractListValuedMap<K,​V>

  • Type Parameters:
    K - the type of the keys in this map
    V - the type of the values in this map
    All Implemented Interfaces:
    ListValuedMap<K,​V>, MultiValuedMap<K,​V>
    Direct Known Subclasses:
    ArrayListValuedHashMap
    public abstract class AbstractListValuedMap<K,​V>
extends AbstractMultiValuedMap<K,​V>
implements ListValuedMap<K,​V>
    Abstract implementation of the ListValuedMap interface to simplify the creation of subclass implementations.

    Subclasses specify a Map implementation to use as the internal storage and the List implementation to use as values.

    Since:
    4.1

    • Constructor Detail

      • AbstractListValuedMap

        protected AbstractListValuedMap()
        Constructor needed for subclass serialisation.

      • AbstractListValuedMap

        protected AbstractListValuedMap​(java.util.Map<K,​? extends java.util.List<V>> map)
        A constructor that wraps, not copies
        Parameters:
        map - the map to wrap, must not be null
        Throws:
        java.lang.NullPointerException - if the map is null

    • Method Detail

      • createCollection

        protected abstract java.util.List<V> createCollection()
        Creates a new value collection using the provided factory.
        Specified by:
        createCollection in class AbstractMultiValuedMap<K,​V>
        Returns:
        a new list

      • get

        public java.util.List<V> get​(K key)
        Gets the list of values associated with the specified key. This would return an empty list in case the mapping is not present
        Specified by:
        get in interface ListValuedMap<K,​V>
        Specified by:
        get in interface MultiValuedMap<K,​V>
        Overrides:
        get in class AbstractMultiValuedMap<K,​V>
        Parameters:
        key - the key to retrieve
        Returns:
        the List of values, will return an empty List for no mapping

      • remove

        public java.util.List<V> remove​(java.lang.Object key)
        Removes all values associated with the specified key.

        A subsequent get(Object) would return an empty list.

        Specified by:
        remove in interface ListValuedMap<K,​V>
        Specified by:
        remove in interface MultiValuedMap<K,​V>
        Overrides:
        remove in class AbstractMultiValuedMap<K,​V>
        Parameters:
        key - the key to remove values from
        Returns:
        the List of values removed, will return an empty, unmodifiable list for no mapping found.